A sun roof unit includes a slide panel, which is attached in an opening of a fixed roof of a vehicle and can be moved backward and forward by a push-pull cable and whose rear end can be tilted in the vertical direction. The push-pull cable is pushed and pulled by rotating a motor, which has a speed reduction unit, in the opposite directions, so that the slide panel can be opened and closed. A DC brush motor is mainly used as a drive source.
Conventional control devices for opening and closing a slide panel will be explained. For example, absolute positions of a sun roof and rotational directions of a motor are detected by a pair of rotation number sensors, which detect rotation number of the motor, and means for detecting a position of the slide panel with respect to a reference position (see Japanese Patent Gazette No. 2002-89133); Output pulses of Hall ICs are divided into pulses for tilting action and pulsed for sliding actions, and they are respectively counted by a first counter and a second counter (see Japanese Patent Gazette No. 2001-180283); and rotational number of a motor shaft and rotational number of an output shaft, which engages with the motor shaft, are respectively detected, and rotational number of a motor is counted on the basis of edges of output shaft detection signals (see Japanese Patent Gazette No. 2001-30763).
In each of the above described technologies for controlling the sun roof, a rectifier (commutator) and a DC brush motor are used, and the sun roof is moved above a head of a driver, etc., so loud sliding noises are created between the commutator and a brush when the motor is driven. Therefore, reducing the noises, which are created when the sun roof is opened and closed, is required.
A plurality of independent sensors for detecting rotational number of the motor and positions of the slide panel must be provided so as to control the tilting action and the sliding action, so that number of parts must be increased, production cost must be increased and complex control must be required.
If a rotor diameter (outer diameter) of the motor is great, a balance is disrupted so that vibrations of the motor are transmitted to the slide panel via a speed reduction mechanism and a push-pull cable and vibration noises are created. A sun roof drive device is provided in a narrow space of a fixed roof, so it must be small in size. Further, a low voltage source (battery), whose voltage is relatively low and which is capable of maintaining enough torque, is required.